1. Field to the Invention
This invention relates to a method and apparatus for securing a connector to a pipe for establishing a sealed connection between the pipe and the connector.
Typically, such a connection will be established between a relatively thin walled metal pipe and a connector for use in a high pressure hydraulic circuit.
2. Description of Prior Art
One method of securing a collector to a pipe is disclosed in DE No. 19 57 565 which teaches the use of a pre-assembly step and a final assembly step wherein, during the pre-assembly step, a clamping ring having radially inwardly directed cutting teeth is located around an end portion of a pipe and is then pressed into a bush provided with an inner conical surface with an axial force imparted to the clamping ring by hydraulic means. In this patent specification, the hydraulically applied axial force is pressure limited by a valve and, for each diameter of pipe, a special die insert is provided which also serves as an adjustment means for the hydraulic pressure limitation. The purpose of this arrangement is that the pre-assembly force is adaptable to the respective pipe diameter and thus to the size of the clamping ring.
A disadvantage of this arrangement is that there is no certainty that the clamping ring teeth will be brought into complete cutting engagement with the pipe during the pre-assembly step whereby, during the final assembly of the connector to the pipe, undefined further cutting of the clamping ring teeth into the pipe may take place together with radially inward deformation of the pipe. Thus there is no certainty that the engagement between the clamping ring teeth and the pipe will be sufficient to resist axial pull-out of the pipe from the clamping ring after final assembly of the connector especially during pulsed hydraulic loads within the hydraulic circuit.